The purpose of this study is to conduct a 6-week clinical trial to determine if NMES plus lumbar stabilization exercises is superior to lumbar stabilization exercises for improving back muscle size, activity, and side-to-side (i.e. right side versus left side) symmetry in older adults with chronic low back pain (i.e. low back pain of greater than 3 months). Muscle size, activity, and symmetry will be assessed using US before and after the treatments to determine if the treatments positively impact muscle. Secondary clinical measures of success will include improvements in physical, psychological, and social function pre- to post-treatment.